A fault detection technique based on line parameters in ring-configured DC microgrid

Abstract

Abstract The integration of distributed generation (DG) units into a DC microgrid presents a research challenge in terms of a proper protection scheme. The network must be protected due to the sudden change in the amplitude and direction of the fault current. In addition, due to the absence of zero-crossing of the DC fault current, protecting the network from these potential faults is a challenging task. The DC fault can be diagnosed using an appropriate detection technique after monitoring the movement of current. In this paper, a least-square estimation (LSE) technique has been adopted, which has been proven to be able to detect the faulty line strongly, so that the fault is detected by estimated parameters. This fault detection technique has been evaluated on six-lines, with faults analyzed on each line. The six-bus DC microgrid is designed in PSS®SINCAL, and the proposed method is simulated in MATLAB. Two sets of simulations are designed to validate the reliability of the proposed method: (1) pole–ground (P–G) and (2) pole–pole (P–P) fault estimation of inductance and capacitance (C) in a separate line. Simulation results show that the proposed methodology can able to accurately detect (i.e., 95% accuracy) the faulty line in the DC microgrid with respect to designated ‘trip’ value. Thus, the proposed fault detection methodology can be utilized for protection of modern DC microgrids. An experimental PV-battery-load-based fault detection technique has been developed in the laboratory and tested under P–P fault conditions in order to validate the effectiveness of the proposed scheme.