Fault Location in DC Microgrids Based on a Multiple Capacitive Earthing Scheme

This article presents a new method for locating faults along feeders in a direct current (dc) microgrid using a multiple capacitive earthing scheme. During fault conditions, capacitors within the earthing scheme are charging by transient currents that correlate with the fault distance and resistance. Therefore, by assessing the response of the capacitive earthing scheme during the fault, the distance to fault is estimated. The proposed method utilizes instantaneous current and voltage measurements (obtained from the feeder terminals and earthing capacitors) applied to an analytical mathematical model of the faulted feeder. The proposed method has been found to accurately estimate the fault position along the faulted feeder, and the systematic evaluation has been carried out to further scrutinize its performance under different loading scenarios and highly resistive faults. In addition, the performance and practical feasibility of the proposed method have been experimentally validated by developing a low-voltage laboratory prototype and testing it under a series of test conditions.