Analysis of the Influence of Voltage Recovery Process on Line Selection Device When Single-phase Grounding Fault Is Removed

The behavior of line protection device with line selection function after single-phase grounding fault occurred in non-effectively grounded system is analyzed. After the fault line was selected and tripped, due to the long attenuation time of zero sequence voltage, the device misjudged that the fault was not removed, and wrongly reclosed the fault line, which led to the further development of the fault. In this paper, the voltage recovery process after fault is removed is analyzed and verified by simulation test. Finally, considering the influence of voltage recovery process, an optimal algorithm applicable for various types of line selection devices is proposed to accurately judge whether the fault is removed after the line is selected and tripped, and to improve the operation accuracy of the whole process of single-phase grounding fault.