TN-C、TN-S、TN-C-S、TT系统区别

1、Pushing a head,Ea st,North,We st devel opment,facilitating shanty,completexinche ngWest Roa d, stability andre construction ofthestreet,Star Ding garde n builtce nturyGar den District,subject publichousing construction,heati ng thegas expa nsi on a cceleratedimpleme ntation,JingRuiRiver andbridgesty

2、leline solidshaft,furtherexpanded thetown devel opme nt.Beautiful countryadheretot headva nceand ty picalfor agroup t o lead.According t o "ecol ogicallay base d,and industry i ncreased income ,and l ive upgra de civi lization,and culture richconnotation"of thought, caug ht built beautiful

3、village,and wholevillageadvance,a nd easily relocation, and"five modifiedthreebuilt",proje ctnear30 a; depthinto e col ogical, a nd industry,a nd cult ure,and tourism,elements, hig hstandards caught partyorigi nalcity Liu, and ja deareXiaAO,m odelvill age,in provinceCity sethas benchmark.F

4、 our is e qualbe nefitstopr omot e sharing, coordinateddevel opme ntofvarious socialundertakings.In thecase ofrigid spendi ng slowing reve nuegrowth, increase, financial75%tothe people's liveli hood,t he masse shave morea ccess inthesharing. Cuoba n somet hinggood a nd benefit.A dheretot heaffor

5、dabl e,best ,carefully cuoban v illageoil ,water and heat,cultural, cityand Countycolumns practical ,devel opment s be nefitfamilies,bringmorewelfareto themasses.Developme nt ofsocialconve nience.A cce ptance of bala nced developmentofcompulsoryeducationthroug h the nationalasse ssment,t heCounty vo

6、cational e ducation center wa s named "top Schoolofvocationale ducation inChina",the thirdbatch ofnationalreformanddevelopmentmodelthroughprovi ncial.Five isto dee pen reform a nd innovation to break bottlene cks a ndendoge nous development ofeffective fire.Asanengine of dynamism,a ddi ng

7、reform keytoa dopting reformmeasures stressenergyandbre ak bottlene cks a nd promoti ng devel opme nt. Pay close attenti on to thekeyareaofr eform.Consci entiouslyim plementt hepr ovincial depl oymenta nd cancel,a djustment,to undertaketheadministrativeapprovalitemsaccordi ng toRegulati on 347 tof u

8、rtherimpr oveadmi nistrativeefficiencyconti nui ngdeepe ning reformforpovertya lleviat ion,spee ding up r ural landright regi stration certification pilot pr oject,encouraging theorderly transfer ofland management,utilize the land resource s,in order topromote scale ma nagement l aidt he Foundation.

9、Activelycultivatet he market. Firmlyestablishamarket-ori ented, nurturingfamilyfarms,industrialusers,professionalcooperationorganizati on new market managementmain body 456,effectively improvetheindustry, intensive andmarketizationofencouragingsupportsocialcapitali nto the small micro -credit,urban

10、development, culture andtourism,publicservi ces a nd otherarea s,easi ng devel opment shortfall.Topr omote m assi nnovation.To supportthe ruralse ctorto usenewthi nkinga ndnew idea s,creative w ork incentive s such a s actively pr omoting fina ncial intermediati on, bring a dded 159i n non publi c e

11、nter prises,i ndivi dua lly-1540, create daTN-C 系统、 TN-S 系统、 TN-C-S 系统、 TT 系统的区别：建筑工程供电使用的基本供电系统有三相三线制三相四线制等，但这些名词术语内涵不是十分严格。国际电工委员会（ IEC ） 对此作了统一规定，称为 TT 系统、 TN系统、 IT 系统。其中TN 系统又分为TN-C 、 TN-S 、 TN-C-S 系统。下面内容就是对各种供电系统做一个扼要的介绍。一，工程供电的基本方式5/6/2010 10:22:32 AM根据 IEC 规定的各种保护方式、术语概念，低压配电系统按接地方式的不同分为三类，即

12、TT 、 TN 和 IT 系统，分述如下。（1 ） TT 方式供电系统TT 方式是指将电气设备的金属外壳直接接地的保护系统，称为保护接地系统，也称TT 系统。第一个符号T 表示电力系统中性点直接接地；第二个符号T 表示负载设备外露不与带电体相接的金属导电部分与大地直接联接，而与系统如何接地无关。在 TT 系统中负载的所有接地均称为保护接地，这种供电系统的特点如下。1 ）当电气设备的金属外壳带电（相线碰壳或设备绝缘损坏而漏电）时，由于有接地保护，可以大大减少触电的危险性。但是，低压断路器（自动开关）不一定能跳闸，造成漏电设备的外壳对地电压高于安全电压，属于危险电压。2 ）当漏电电流比较小时，即使

13、有熔断器也不一定能熔断，所以还需要漏电保护器作保护，因此TT 系统难以推广。3 ） TT 系统接地装置耗用钢材多，而且难以回收、费工时、费料。现在有的建筑单位是采用TT 系统，施工单位借用其电源作临时用电时，应用一条专用保护线，以减少需接地装置钢材用量。把新增加的专用保护线PE 线和工作零线N 分开，其特点是：共用接地线与工作零线没有电的联系；正常运行时，工作零线可以有电流，而专用保护线没有电流；TT 系统适用于接地保护点很分散的地方。（2 ） TN 方式供电系统这种供电系统是将电气设备的金属外壳与工作零线相接的保护系统，称作接零保护系统，用TN 表示。它的特点如下。1 ）一旦设备出现外壳带电

14、，接零保护系统能将漏电电流上升为短路电流，这个电流很大， 是 TT 系统的 5.3 倍， 实际上就是单相对地短路故障，熔断器的熔丝会熔断，低压断路器的脱扣器会立即动作而跳闸，使故障设备断电，比较安全。2 ） TN 系统节省材料、工时， 在我国和其他许多国家广泛得到应用，可见比 TT 系统优点多。TN 方式供电系统中，根据其保护零线是否与工作零线分开而划分为TN-C 和 TN-S 等两种。ent l aidt he Foundation.Activelycultivatet he market. Firm lyesta blish amarket-ori ented, nurturing fam

15、ilyfarms,industrialusers,professionalcooperationorganizati on new market ma nagementmai n body 456,effectively improvethe industr y, intensive andndustry,a nd cult ure,and tourism,elements, hig hstandards ca ught partyorigi nalcity Liu, and ja deare XiaAO,m odelvill age,in provinceCity sethas benchm

16、ark.F our is e qualbe nefitsto promotesharing, coordinate ddevel opme ntofvarious social undertakings.（ 3 ） TN-C 方式供电系统它是用工作零线兼作接零保护线，可以称作保护中性线，可用NPE 表示（ 4 ） TN-S 方式供电系统它是把工作零线N 和专用保护线PE 严格分开的供电系统，称作TN-S 供电系统， TN-S 供电系统的特点如下。1 ） 系统正常运行时，专用保护线上不有电流，只是工作零线上有不平衡电流。PE线对地没有电压，所以电气设备金属外壳接零保护是接在专用的保护线PE 上，

17、安全可靠。2 ）工作零线只用作单相照明负载回路。3 ）专用保护线PE 不许断线，也不许进入漏电开关。4 ）干线上使用漏电保护器，工作零线不得有重复接地，而PE 线有重复接地，但是不经过漏电保护器，所以TN-S 系统供电干线上也可以安装漏电保护器。5 ） TN-S 方式供电系统安全可靠，适用于工业与民用建筑等低压供电系统。在建筑工程工工前的“三通一平”（电通、水通、路通和地平- 必须采用TN-S 方式供电系统。1 ）国际电工委员会（ 源）系统对地关系。如5/6/2010 10:48:21 AMIEC ）规定的供电方式符号中，第一个字母表示电力（电T 表示是中性点直接接地；I 表示所有带电部分绝缘

18、。6 ）第二个字母表示用电装置外露的可导电部分对地的关系。如T 表示设备外壳接地，它与系统中的其他任何接地点无直接关系；N 表示负载采用接零保护。7 ）第三个字母表示工作零线与保护线的组合关系。如C 表示工作零线与保护线是合一的，如TN-C ； S 表示工作零线与保护线是严格分开的，所以PE 线称为专用保护线，如TN-S 。 N 系统：电源变压器中性点接地，设备外露部分与中性线相连。系统：电源变压器中性点接地，电气设备外壳采用保护接地。系统：电源变压器中性点不接地（或通过高阻抗接地），而电气设备外壳电气设备外壳采用保护接地。1、 TN 系统 5/6/2010 10:52:49 AMPushin

19、g a head,Ea st,North,We st devel opment,facilitating shanty,completexinche ngWest Roa d, stability andre construction ofthestreet,Star Ding garde n builtce nturyGar den District,subject publichousing construction,heati ng thegasexpa nsi on a ccel eratedim pleme ntation,JingRuiRiver andbridgestylelin

20、e solidshaft,furtherexpanded thetow n devel opme nt.Beautiful countryadheretot headva nceand ty picalfor agroupt o lead.According t o "ecol ogicallaybase d,and industry increased income ,and l ive upgra de civi lization,and culture ri chconnotati on" of thought, caug ht built beautifulvill

21、age,andwholevillagea dvance,a nd eas ilyrelocation, and "fivemodified threebuilt",projectnear30 a; depthinto e col ogical, a nd industry,a nd cult ure,and tourism,elements, hig hstandards ca ught partyorigi nalcityLiu, and ja deare XiaAO,m odelvill age,in provinceCity sethas benchmark.F ou

22、r is e qualbe nefits to pr omotesharing,coordinateddevel opme ntofvarious socialundertakings.In thecase ofrigid spendi ng slowing reve nuegrowth, increase, financial75%tothe people's liveli hood,t he masse shave morea ccess inthesharing. Cuoba n somet hinggood a nd benefit.A dheretot heaffordabl

23、 e,best ,carefully cuoban v illageoil ,water and heat,cultural, city andCounty colum ns practical ,devel opment s be nefitfamilies,bringmorewelfare to themasses.Developme nt ofsocialconve nience.A cce ptance of bala nced developmentofcompulsory e ducationt hroug h the nationalassessment,t heCounty v

24、ocational e ducation center wa s named "top Schoolofvocati onale ducation inChina",the thirdbatchofnationalreformanddevelopmentmodelthroughprovi ncial.Five isto dee pen reform a nd innovation to break bottlene cks a ndendoge nous development ofeffective fire.Asanengi ne of dynamism,a ddi n

25、g reform keytoa dopting reformmeasures stressenergyandbre akbottlene cks a nd promoti ng devel opme nt. Payclose attenti on to thekeyarea s ofr eform.Consci entiouslyim plementt hepr ovincial depl oymenta nd cancel,a djustment,to undertaketheadministrativeapprovalitemsaccordi ng toRegulati on 347 to

26、f urtherimproveadmi nistrativeefficiencyconti nui ngd eepe ning reformforpovertya lleviation,spee ding up r ural landright regi stration certification pilotpr oject,encouraging t heor derly transfer of landmanagement,utilizethe landresources,in order topromote scale ma nagement l aidt he Foundation.

27、Activelycultivatethe market. Firmlyestablish amarket-oriented, nurturingfamilyfarms,industrialusers,professionalcooperationorganization new market ma nagementmain body 456,effectively improvetheindustry, intensive andmarketizationofencouragingsupportsocialcapitali nto the small micro -credit,urban d

28、evelopment, culture andtourism, publicservi ces a nd otherarea s,easi ng devel opment shortfall.To pr omote mass i nnovation.To supportthe ruralse ctorto usenewthi nkinga nd newidea s,creative w ork incentive s such a s activelypr omoting fina ncial intermediati on, bring a dded 159i n non publi c e

29、nter prises,i ndivi dua lly-1540, create da电力系统的电源变压器的中性点接地，根据电气设备外露导电部分与系统连接的不同方式又可分三类：即TN-C 系统、 TN-S 系统、 TN-C-S 系统。下面分别进行介绍。1.1、 TN-C 系统其特点是：电源变压器中性点接地，保护零线（PE）与工作零线（N）共用。（）它是利用中性点接地系统的中性线（零线）作为故障电流的回流导线，当电气设备相线碰壳，故障电流经零线回到中点，由于短路电流大，因此可采用过电流保护器切断电源。TN-C 系统一般采用零序电流保护；（2） TN-C 系统适用于三相负荷基本平衡场合，假如三相负

30、荷不平衡，则PEN 线中有不平衡电流，再加一些负荷设备引起的谐波电流也会注入PEN，从而中性线N带电，且极有可能高于，它不但使设备机壳带电，对人身造成不安全，而且还无法取得稳定的基准电位；（3） TN-C 系统应将PEN 线重复接地，其作用是当接零的设备发生相与外壳接触时，可以有效地降低零线对地电压。由上可知，TN-C 系统存在以下缺陷：（）当三相负载不平衡时，在零线上出现不平衡电流，零线对地呈现电压。当三相负载严重不平衡时，触及零线可能导致触电事故。（）通过漏电保护开关的零线，只能作为工作零线，不能作为电气设备的保护零线，这是由于漏电开关的工作原理所决定的。（）对接有二极漏电保护开关的单相用

31、电设备，如用于TN-C 系统中其金属外壳的保护零线，严禁与该电路的工作零线相连接，也不答应接在漏电保护开关前面的PEN 线上，但在使用中极易发生误接。（）重复接地装置的连接线，严禁与通过漏电开关的工作零线相连接。Pushing a head,Ea st,North,We st devel opment,facilitating shanty,completexinche ngWest Roa d, stability andre construction ofthestreet,Star Ding garde n builtce nturyGar den District,subject pu

32、blichousingconstruction,heati ng thegas expa nsi on a cceleratedimpleme ntation,JingRuiRiver and bridge style line solidshaft,furtherexpanded thetow n devel opme nt.Beautiful countryadheretot headva nceand ty picalfor agroup t o lead.According t o "ecol ogicallaybase d,and industry i ncreased i

33、ncome ,and l ive upgra de civi lization,and culture ri chconnotati on" of thought, caug ht built beautifulvillage,andwholevillageadvance,a nd easily relocation, and"five modifiedthreebuilt",projectnear30 a; depthinto e col ogical, a nd industry,a nd cult ure,and tourism,elements, hig

34、hstandards caught partyoriginalcityLiu, and ja deareXiaAO,m odelvill age,inprovinceCity sethas benchmark.F our is equalbe nefitstopromotesharing,coordinateddevel opmentofvarious socialundertakings.In thecase ofrigid spendi ng slowing reve nuegrowth, increase, financial75%tothe people's liveli ho

35、od,t he masse shave morea ccess inthesharing. Cuoba n somet hinggood a nd benefit.A dheretot heaffordable,best ,carefully cuoban v illageoil ,water and heat,cultural, cityand Countycolum ns practical devel opment s be nefitfamilies,bringmorewelfare to themasses.Developme nt ofsocialconve nience.A cc

36、e ptance of bala nced developm ent of compul sory e ducationt hroug h the nationalasse ssment,t heCounty vocational e ducation center wa s named "top Schoolofvocationaleducation inChina",the thirdbatchofnationalreformanddevelopmentmodelthroughprovi ncial.Five isto dee pen reform a nd innov

37、ation to break bottlene cks a ndendoge nous development ofeffective fire.Asanengi ne of dynamism,a ddi ng reform keytoa dopting reformmeasures stressenergyand break bottlene cks a nd promoti ng devel opme nt. Pay close attenti on to thekey area s ofr eform.Consci entiouslyim plementt hepr ovincial d

38、epl oymenta nd cancel,a djustment,to undertaketheadministrativeapprovalitemsaccording toRegulati on 347 tof urtherimproveadmi nistrativeefficie ncyconti nui ngdeepe ning reformforpovertya lleviation,spee ding up r ural landright regi stration certification pilotproject,encouraging theorderly transfe

39、r ofland management,utilize the landresource s,in order topromote scale ma nagement l aidt he Foundation.Activelycultivatethe market. Firmlyesta blish amarket-oriented, nurturingfamilyfarms,industrialusers,professionalcooperationorganizati onnew market managementmain body 456,effectively improvethe

40、industry, intensive andmarketizationofencouragingsupportsocialcapitali nto the small micro -credit,urban development, culture andtourism, publicservi ces a nd otherarea s,easi ng devel opment shortfall.Topr omote mass i nnovation.To supportthe ruralse ctorto usenewthi nkinga nd newidea s,creative wo

41、rk incentive s such a s activelypr omoting fina ncial intermediati on, bring a dded 159i n non publi c enter prises,i ndivi dua lly-1540, create daTN-S 供电系统，将工作零线与保护零线完全分开，从而克服了TN-C 供电系统的缺陷，所以现在施工现场已经不再使用TN-C 系统。1.2、 TN-S 系统整个系统的中性线（N）与保护线（PE）是分开的。（）当电气设备相线碰壳，直接短路，可采用过电流保护器切断电源；（）当N 线断开，如三相负荷不平衡，中性点

42、电位升高，但外壳无电位，PE 线也无电位；（）N- 系统PE线首末端应做重复接地，以减少PE 线断线造成的危险。（）N- 系统适用于工业企业、大型民用建筑。目前单独使用独一变压器供电的或变配电所距施工现场较近的工地基本上都采用了 N-系统，与逐级漏电保护相配合，确实起到了保障施工用电安全的作用，但N- 系统必须注重几个问题：（）保护零线绝对不答应断开。否则在接零设备发生带电部分碰壳或是漏电时，就构不成单相回路，电源就不会自动切断，就会产生两个后果：一是使接零设备失去安全保护；二是使后面的其他完好的接零设备外壳带电，引起大范围的电气设备外壳带电，造成可怕的触电威胁。因此在JGJ46-88施工现场

43、临时用电安全技术规范规定专用保护线必须在首末端做重复接地。（）同一用电系统中的电器设备绝对不答应部分接地部分接零。否则当保护接地的设备发生漏电时，会使中性点接地线电位升高，造成所有采用保护接零的设备外壳带电。（）保护接零PE 线的材料及连接要求：保护零线的截面应不小于工作零线的截面，并使用黄/绿双色线。与电气设备连接的保护零线应为截面不少于2.5mm2 的绝 缘多股铜线。保护零线与电气设备连接应采用铜鼻子等可靠连接，不得采用铰接；Pushing a head,Ea st,North,We st devel opment,facilitating shanty,completexinche ng

44、West Roa d, stability andre construction ofthestreet,Star Ding garde n builtce nturyGar den District,subject publichousingconstruction,heati ng thegasexpa nsi on a ccel eratedim pleme ntation,JingRuiRiver andbridge style line solidshaft,furtherexpanded t hetow n devel opme nt.Beautiful countryadhere

45、tot headva nceand ty picalfor agroupt o lead. According t o "ecol ogicallaybase d,and industry i ncreased income ,and l ive upgra de civi lization,and culture ri chconnotati on" of thought, caug ht built beautifulvillage,andwholevillagea dvance,a nd eas ilyrelocation, and "fivemodifie

46、d threebuilt",projectnear30 a; depthintoecol ogical, a nd industry,a nd culture,and tourism,elements,hig hstandards ca ught partyoriginalcityLiu, and ja deareXiaAO,modelvill age,in provinceCity sethas benchmark.Four is e qualbe nefits to pr omotesharing,coordinateddevel opme ntofvarious socialu

47、ndertakings.In thecase ofrigid spendi ng slowing reve nuegrowth, increase, financial75%tothe people's liveli hood,t he masse shave morea ccess inthesharing. Cuoba n somet hinggood a nd benefit.A dheretot heaffordable,best ,carefully cuoban v illageoil ,water and heat,cultural, city andCounty col

48、um ns practical ,devel opment s be nefitfamilies,bringmor ewelfare to themasses.Devel opme nt ofsocialconve nience.A cce ptance of bala nced developmentofcompul sory e ducationt hroug h the nationalasse ssment,t heCounty vocational e ducation center wa s named "top Schoolofvocationaleducation i

49、nChina",the thirdbatchofnationalreformanddevelopmentmodelthrough provi ncial.Five isto dee pen reform a nd innovation to break bottlene cks a ndendoge nous development ofeffective fire.Asanengi ne of dynamism,a ddi ng reform keytoa dopting reformmeasures stressenergyand breakbottlene cks a nd p

50、romoti ng devel opme nt. Payclose attenti on to thekeyarea s ofr eform.Consci entiouslyim plementt hepr ovincial depl oymenta nd cancel,a djustment,to undertaketheadmini strativeapprovalitemsa ccordi ng toRegulati on 347 tof urtherimproveadmi nistrativeefficie ncyconti nui ngd eepe ning reformforpov

51、ertya lleviation,spee ding up r ural landright regi stration certification pilotproject,encouraging theor derly transfer of landmanagement,utilizethe landresource s,in order topromote scale ma nagement l aidt he Foundation.Activelycultivatethe market. Firmlyestablish amarket-oriented, nurturingfamil

52、yfarms,industrialusers,professionalcooperationorganizati on new market managementmain body 456,effectively improvethe industry, intensive andmarketizationofencouragingsupportsocialcapitali nto the small micro -credit,urban development, culture andtourism, publicservi ces a nd otherarea s,easi ng dev

53、el opment shortfall.To pr omote mass i nnovation.To supportthe ruralse ctorto usenewthi nkinga nd newidea s,creative w ork incentive s such a s activelypr omoting fina ncial intermediati on, bring a dded 159i n non publi c enter prises,i ndivi dua lly-1540, create da电气设备接线柱应镀锌或涂防腐油脂，保护零线在配电箱中应通过端子板连

54、接，在其他地方不得有接头出现。1.3、 TN-C-S 系统它由两个接地系统组成，第一部分是TN-C 系统，第二部分是N- 系统，其分界面在 N 线与 PE 线的连接点。（）当电气设备发生单相碰壳，同N-系统；（）当N 线断开，故障同N-系统；（） TN-C- 系统中PEN 应重复接地，而N 线不宜重复接地。PE 线连接的设备外壳在正常运行时始终不会带电，所以 TN-C- 系统提高了操作人员及设备的安全性。施工现场一般当变台距现场较远或没有施工专用变压器时采取 TN-C- 系统。2、 TT 系统电源中性点直接接地，电气设备的外露导电部分用PE 线接到接地极（此接地极与中性点接地没有电气联系）在采

55、用此系统保护时，当一个设备发生漏电故障，设备金属外壳所带的故障电压较大，而电流较小，不利于保护开关的动作，对人和设备有危害。为消除T 系统的缺陷，提高用电安全保障可靠性，根据并联电阻原理，特提出完善TT 系统的技术革新。技术革新内容是：用不小于工作零线截面的绿/黄双色线（简称PT 线），并联总配电箱、分配电箱、主要机械设备下埋设的4-5 组接地电阻的保护接地线为保护地线，用绿/黄双色线连接电气设备金属外壳。它有下列优点：1）单相接地的故障点对地电压较低，故障电流较大，使漏电保护器迅速动作切断电源，有利于防止触Pushing a head,Ea st,North,We st devel opme

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58、 easily relocation, and"five modifiedthreebuilt",proje ctnear30 a; depthi nto e col ogical, a nd industry,a nd cult ure,and tourism,elements, hig hstandards ca ught partyorigi nalcity Liu, and ja deare XiaAO,m odelvill age,in provinceCity sethas benchmark.F our is e qualbe nefitsto promotesharing, coordinate ddevel opme ntofvarious social undertakings.In thecase ofrigid spendi ng slowing reve nue