Abstract：Despite bringing several benefits to modern power systems，distributed generation（DG）and

microgrids cause a significant impact on the operation of power distribution networks，especially with regard to the

protection system. In this new scenario，the adoption of smart protection systems capable of incorporating advanced control and protection mechanisms is of paramount importance for ensuring the automatic reconfiguration and restoration of the power grid when undesirable phenomena like faults occur. Considering this scenario，a novel metaheuristic called adaptive fuzzy directional bat algorithm（AFDBA）was proposed，which can calculate the optimal setting of directional overcurrent relays（DOCRs）in the power grid without the need for tuning the initial parameters. The technique was applied to two case studies，that is，the 3-bus and 30-bus test systems. The algorithm performance was compared with that of mayfly optimization algorithm，elephant herding optimization（EHO），bat algorithm（BA），and directional bat algorithm（DBA）. The results evidence that the proposed approach has high convergence speed，high robustness，and acceptable computational burden，while providing the proper coordination of protection systems.

      Key words：distributed generation（DG）；optimization；protections systems；microgrids；adaptive fuzzy

directional bat algorithm（AFDBA）