With the rapid development of electrical power systems in recent years

microgrids (MGs) have become increasingly prevalent. MGs improve network efficiency and reduce operating costs and emissions because of the integration of distributed renewable energy sources (RESs)

energy storage

and source-load management systems. Despite these advances

the decentralized architecture of MGs impacts the functioning patterns of the entire system

including control strategy

energy management philosophy

and protection scheme. In this context

developing a convenient protection strategy for MGs is challenging because of various obstacles

such as the significant variance in short-circuit values under different operating modes

two-way power flow

asynchronous reclosing

protection blinding

sympathetic tripping

and loss of coordination. In light of these challenges

this paper reviews prior research on proposed protection schemes for AC-MGs to thoroughly evaluate network protection's potential issues. The paper also provides a comprehensive overview of the MG structure and the associated protection challenges

solutions

real applications

and future trends.