New Method for Single-phase-grounded Fault Location in Small Current Grounding System

Abstract

Based on the analysis of the single-phase-grounded fault characteristics in ungrounded systems, a single-end fault location method was proposed which is built on the zero-sequence voltage calculation at the fault point and impedance method. It calculates each phase voltages of the line fault point by introducing the connection between the line loss and the fault distance into the zero-sequence voltage trajectory calculation process. At the same time, combining the current characteristics of the ungrounded neutral point system, the functional relationship of the fault distance was deduced, with respect to the voltage difference between the voltage at the beginning of the fault and the fault point, and the fault location function was constructed according to the Kirchhoff voltage equation. The PSCAD/EMTDC platform is used to build the power cable model. The simulation verification of this method is carried out under the single-phase ground fault. The results show that the algorithm can complete the fault location without detecting the fault current data, and has a certain degree of robustness to the changes in load and fault resistance.