Line Selection Method of Small Current Grounding System Based on Transient Characteristic Parameters

When a single-phase grounding fault occurs in a small current grounding system, the accuracy of the line selection result is greatly affected by the initial phase angle of the fault and the hi gh-resistance grounding. Due to the compensation effect of the ar c suppression coil, the line selection information is extremely wea k, and it is difficult to select the fault line. Therefore, this paper p roposes a ' pulse stacking polarity line selection method ', which s tacks the fault information in a quarter of the period after the fau It occurs, and combines the polarity of the stacking point to const ruct the line selection reliability rate to complete the fault line sele ction. The proposed algorithm is verified by MATLAB/Simulink simulation, and the algorithm is compared with the modulus max imum method and the pulse polarity direct line selection method. The results show that the line selection algorithm has high accura cy and reliability, and has strong robustness to different fault initi al conditions. And when the ' line selection information ' is misse d, the fault line can still be selected.