根据IEC 60364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 TT 、 TN 和 IT 系统。 1.TT系统TT grounding system TT供电系统: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。其中,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...
To provide protection at home from damages arising from lightning, electrical shock or electromagnetic waves, the TN grounding system that is internationally popular and the TT grounding system that is used in Japan were evaluated to compare their performances. The test proved the superiority of the...
TN system: the neutral grounding of the power transformer, the exposed part of the equipment is connected with the neutral line. TT system: neutral grounding of power transformer, protective earthing of electric equipment enclosure. IT system: ungrounded neutral power transformer (or through high ...
30、ality of ground wire and ensure the grounding resistance of 10 or less q, electric safety protection more reliablett system is widely used in foreign countries, in china is limited to local docking to the electronic equipment situation of high demand, at present in the construction site gen...
earth, and how the system grounding. In the TT system, all the ground of the load is called a protective ground, as shown in figure 1-1. The features of this power supply system are as follows.供电线路TN, TT ,I T系统(国外英文资料)供电线路TN, TT ,IT系统Power suppl y mode; TT sys...
1)TN-S systemTN-S系统 1.Through the calculation of example, the short circuit current value of single phase grounding and the voltage of short circuit point were compared in TN-S system for the four cases i.通过实例计算,比较了TN-S系统在无重复接地、有重复接地、有重复接地且PE线截面比相线低...
system. TNsystem:powertransformerneutralgrounding,theexternal partoftheequipmentisconnectedtotheneutralline. TTsystem:powertransformerneutralgrounding,electrical equipmentshelladoptprotectivegrounding. ITsystem:theneutralpointofthepowertransformerisnot grounded(orthroughhighimpedancegrounding),whilethe ...
But if the utility transformer is used and other users use the TT system, the system shall be adopted at the construction site. The live part of a power system has no direct connection (or resistance to grounding) between the earth and the earth, The exposed part of the receivin device ...
TT system: the neutral ground of the power transformer, the electric equipment case is protected to ground. IT system: the power transformer is not grounded in neutral (or through high impedance grounding), and the electric device case is protected by the shell. TN system Power transformer ...
This paper focuses on the analysis of distribution protectionfor single-phase grounding fault when TN-S system is used in municipal road lighting distribution system,and gives reasonable suggestions.Keywords:TN-S grounding system; single-phase grounding fault; residual current; euipotential bonding作者...