A simple approach of fault identification and localization for low-voltage DC microgrid

Abstract

DC microgrid provides the horizontal infrastructures to integrate distributed generation (DG) and loads. The protection of DC microgrid is a quite challenging task. Unlike conventional AC system, the DC system cannot survive or sustain high-magnitude fault currents. The nodal analysis with overcurrent (NAOC) scheme is proposed for fault detection and isolation in the service main and DC bus without de-energizing the complete low voltage DC microgrid. This avoids the complete shutdown of the DC bus with continuity of supply through other buses due the use of ring main DC bus. The algorithm for fault location and finding its resistance are also developed. The proposed scheme has been verified with the computer simulations. The proposed algorithm is implemented, executed and analyzed by supervisory control and data acquisition (SCADA) system at individual nodes during different faults conditions. It is found that the DC microgrid is protected at DG zones, service main fault zones and the DC bus fault zones with the proposed algorithm.