Fault Detection in IEEE 9-Bus DC Microgrid System using Differential Current Method

The fault current in DC microgrids changes quickly compared to conventional AC power systems. This is due to low passivity-based distributed energy resources in DC microgrids that transfer power through electronic converters. Additionally, due to the limited magnitude of fault current, fault detection and identification is an additional challenging task. This paper proposes a new effective protection system for rapid short-circuit detection and isolation of faults in a 9 bus DC microgrid system. This is accomplished by allowing, via a cumulative sum of differential forward and reverse current based method, the fault Isolation by a solid-state circuit breaker action. The faulty line is identified through boundary analysis of locally measured current and voltage signals. The defective branch is isolated by a trip at each node in the system. Finally, two tests of simulation results of the system under pole-pole fault in PSS®SINCAL have been designed which achieve the reliability of the method. The simulation result showed that the system fault can be isolated by a trip at each node in the system.