HBBO-based Intelligent Setting and Coordination of Directional Overcurrent Relays Considering Different Characteristics

Different equipment is used to protect nowadays power systems. Among these protection tools, the directional overcurrent relays (DOCRs) have significant effect in protecting power systems. A sophisticated protection scheme is expected to detect a fault and command as fast as possible, so that the primary relay should detect the fault or else, the backup relay must act after an intended delay. Thus, in such a protection scheme, coordination between the primary and backup relays is important. The conventional coordination methods are not appropriate for the new complex power systems; therefore, the optimal coordination schemes currently are getting more attention. In this paper, a human behavior-based optimal (HBBO) coordination scheme is presented for coordination of DOCRs to provide the maximum coordination between the primary and backup relays. Also, in contrast to the previous methods, different relay characteristics have been used as decision variables in the modeling process so that the optimization algorithm elects the best characteristic for the DOCRs. The proposed protection scheme has been studied and examined using a standard power system structure and it has been demonstrated that using the HBBO algorithm and considering the relay characteristics as decision variables, not only set the miscoordinations to zero but also reduce the operation time of the DOCRs in comparison to other coordination methods.