This document discusses protection schemes for inverter-based microgrids. It begins by defining system protection and apparatus protection in conventional grids. It then defines microgrids and their operating modes of grid-connected and islanded. Challenges in microgrid protection include bidirectional power flow, different operating modes and fault current levels. Various proposed protection schemes are described for the islanded and grid-connected modes, including adaptive directional overcurrent, travelling wave, multi-agent, and pattern recognition schemes. Future microgrid protection is expected to involve communication between relays, machine learning techniques, complex signal processing and fast response times.