网站转让

零序电流互感器保护原理
Protection principle of zero sequence current transformer
零序电流保护具体应用可在三相线路上各装一个电流互感器（CT），或让三相导线一起穿过一零序CT，也可在中性线N上安装一个零序CT，利用这些C.T来检测三相的电流矢量和，即零序电流Io，IA+IB+IC=Io，当线路上所接的三相负荷完全平衡时（无接地故障，且不考虑线路、电器设备的泄漏电流），Io=0；当线路上所接的三相负荷不平衡，则Io=IN，此时的零序电流为不平衡电流IN；当某一相发生接地故障时，必然产生一个单相接地故障电流Id，此时检测到的零序电流IO=IN+Id，是三相不平衡电流与单相接地电流的矢量和。
Zero sequence current protection can be applied to a three-phase line with a current transformer (CT), or a three-phase wire through one zero sequence CT together, or a zero sequence CT on the neutral line N, using these C.T to detect the three-phase current vector and the zero sequence current Io, IA+IB+ IC=Io, when the three-phase load connected to the line is finished. Full balance (without grounding fault, without considering leakage current of circuit and electrical equipment), Io=0; when the three-phase load on the line is unbalanced, then Io=IN, the zero sequence current of this time is unbalance current IN; when a phase occurs grounding fault, a single-phase grounding fault current Id, at this time the detected zero The sequence current IO=IN+Id is the vector sum of the three-phase unbalanced current and the single-phase earth current.