一种利用衰减直流分量的谐振接地系统故障选线方法

New approach for fault line selection in distribution system with arc suppressing coil grounding using decaying DC component

高频暂态量故障选线方法利用的是故障产生的高频分量。当在电压过零附近发生单相接地故障时,引起的高频分量将很少,高频暂态量选线方法灵敏度会大大下降。但电压过零附近故障会引起较大的衰减直流分量,可以构成基于衰减直流分量的暂态量选线方法。分析与仿真表明:对于经消弧线圈接地的小接地电流系统,当线路不在电压最大值附近发生单相接地故障时,故障线路上的衰减直流分量很大,而非故障线路上的衰减直流分量很小;当母线故障时,所有线路上的衰减直流分量都将很小。提出了一种利用衰减直流分量的故障选线方法,用来克服现有高频暂态量选线方法在电压过零附近故障时灵敏度低的缺点。该方法与高频暂态量选线方法集成可以形成完善的故障选线方案。

If a single-phase fault occurs at the faulted phase voltage near zero-cross in distribution system, little of the high frequency component will be caused. So, the fault line selection methods based on high frequency transient component is insensitive. But much of the decaying DC component will be caused in this condition. Therefore, the decaying DC component may be used to build a new fault line selection approach. In distribution system with arc suppression coil grounding, if a single-phase fault occurs on a line at the faulted phase voltage near zero-cross, decaying DC component will be much on faulted line, and little on healthy lines. If a single-phase fault occurs on bus, decaying DC component will be little on all lines. A new approach for selecting faulted line was presented based on decaying DC component, which can be used to overcome the defect that the method based on transient component is insensitive at the faulted phase voltage near zero-cross. A perfect scheme will be work out combining with this method and the method based on transient component.