小电流接地系统单相接地故障选线新发展

分析当前采用的DDA法、模式识别法、小波分析法等不同原理构成的小电流接地系统单相接地故障选线方法，指出这些方法的优缺点：DDA法基本消除过渡电阻的影响但不利于实现；模式识别法具有自适应性和容错性，但样本的提取比较困难而且现场经验不足；小波选线法虽具有快速性、准确性等优点但抗干扰的能力较差，过渡电阻对其也有较大影响。通过这些优缺点的比较，发现这些方法之间存在着一定的互补性，提出了一种利用这种互补性制作一套选线装置的设想。

New development of fault line selection method in small current grounding power system

The development history of the fault line selection method for single phase grounding fault in small current grounding power system is reviewed.Different methods based on different principles are analyzed,such as DDA (Differential Detection using phase to ground Admittance),Pattern Recognition,Wavelet Transform and so on.Their advantages and disadvantages are presented:DDA eliminates the effects of fault resistance,but is not easy in implementation;Pattern Recognition has the characters of self adaptation and error allowance,but the current patterns is hard to get and the field experience is not rich;Wavelet Transform is fast and exact,but its anti interference ability is poor and the influence of fault resistance is great.By comparing their advantages and disadvantages,a collaborating method is found and a concept that applies it to make a suit of fault line selection device is presented.