A Novel Current Based Protection Scheme for Internal/External Fault Detection in Islanded Two Interconnected AC Microgrid

This paper proposes a novel current-based protection scheme for detecting and distinguishing internal from external faults in Interconnected AC Microgrids (IAC-MGs). The proposed protection scheme uses the time domain-based dq0 transformation due to the fault current level being low in islanded IAC-MGs, and a low sensitivity protection scheme to the fault current level is necessary for the protection of MG and IAC-MG. Numerical results in the two IAC-MG test case shows that the proposed protection scheme can detect and distinguish between internal and external faults. Also, the proposed protection scheme has low sensitivity to the fault current level and does not require the communication system for fault detection.