基于“S注入法”的一种故障定位新方法

A new approach of fault location based on “S injecting signal”

依据“S注入法”选线定位原理 ,导出了小电流接地故障情况下 ,故障支路的等效电路、相量图 ,分析了注入信号的频率应选择具有不同于系统固有信号的特征 ,指出了注入的信号电流仅在接地线路接地相中流动 ,不会流向系统的其它部位的特点。针对当接地相的接地电阻大、阻抗角小时 ,普通阻抗法测距精度差 ,提出了以倍角算法为基础的改进算法 ,并给出了理论分析和实现电路。

According to the principle of “S injecting signal”,the paper gives out the equivalent circuit and phase graph of the fault branch,analyzing that the feed current frequency to be chosen should be different from industrial frequency,pointing out the character which the feed current never passes through unfaulted branch,and only flows between the fault branch and the power system ground injection point.In view of the lower accuracy by simple impedance measurement method,the paper gives out a new improved way which is based on double angle theory,analysis of the way in theory and realized circuit