Autonomous protection of low voltage DC microgrid

Regarding high efficiency, DC microgrid has more advantages than AC, but the protection of DC microgrid is a quite challenging task. The conventional protection scheme for DC microgrid uses circuit breaker on AC side, on occurrence of fault AC circuit breaker opens and this cause´s complete shutdown of DC link and introduces a forced outage in the system. This paper presents an autonomous scheme for protection of DC grid. It avoids the complete shutdown of the DC link and continuity of supply is maintained through other buses, as ring type distribution is considered. This system uses current sensors and controller for fault detection and isolation. Whereas diode and resistors used for fault current extinction, as fault current is harmful for converters. After fault, current difference between sending and receiving end are occur, on this current difference controller isolate the faulted section through power switches/IGBT. The efficacy of the said scheme is verified through MATLAB Simulink.