Intelligent over-current protection scheme in inverter-based microgrids

Recently by technological developments in inverterbased devices, application of these prominent apparatus has gained more attention in newly emerged microgrids (MGs). In this paradigm, the concept of multiple inverter-interfaced distributed generations (IIDGs)-based MG is now a reputable term. According to fast dynamic responses of IIDGs, study of their transient behaviors seems essential. Among the important indices of IIDG-based MGs in transient situations, the current index is the most susceptible one, which should not be higher than twice values of rated current due to their physical constraints. This paper proposes a proportional-integral (PI) controller adjoined in the voltage source inverter control loop to well-protect the IIDGs against the possible over currents during short circuit faults in MG. To adapt the PI controller for both connected and autonomous modes and different short circuit faults in MG, fuzzy logic as an intelligent method is employed to fine-tune of the PI gains. The obtained results illustrate the efficiency of fuzzy-based fine tuning approach.