Flexible grounding system fault location method based on steady state projection

Abstract

At present, the grounding protection of flexible grounding system mostly directly adopts the zero-sequence time-limit overcurrent protection of low-resistance grounding system, which has problems such as insufficient protection sensitivity when grounding via high-resistance. The changes in zero-sequence voltage (ZSV) and zero-sequence current (ZSC) upstream and downstream of the fault point before and after the small resistor is put into operation are analyzed. The fault information collected by the synchronous phasor measurement unit (PMU) are orthogonalized. Finally, the correlation coefficient method is utilized to compare the numerical values and polarity of projection amounts between adjacent PMUs. Based on this, a fault location method based on steady-state projection is proposed in this paper. Simulation and on-site test data show that the proposed method can accurately identify the fault section under different fault conditions.