Protection Coordination of Bidirectional Overcurrent Relays Using Developed Particle Swarm Optimization Approach Considering Distribution Generation Penetration and Fault Current Limiter Placement

This article is treated with the protection coordination of bidirectional overcurrent relays (OCRs) in distribution power systems to obtain the best performance at a minimum total time dial setting (TDS). High penetration of distribution generation (DG) into distribution systems may significantly affect the protective system; since they increase the short-circuit level by injecting an extra share of fault current, it results in changes in the power/current flow direction. Accordingly, the fault current limiter (FCL) devices should be utilized to mitigate the short-circuit current. FCLs and DGs both will disturb the protection settings of protective equipment. The characteristics and the set point of inverse time relays depend on the fault clearing time (FCT) and the pick-up current. Therefore, an optimization approach is required to minimize the FCTs and TDSs of main relays and backup ones to protect all equipment. Moreover, this strategy selects the optimal placement of the FCL cooperatively according to the cost minimization. The optimization approach is implemented based on the particle swarm optimization (PSO) method within an extra parameter to improve the convergence speed and find the global solution, especially at initial iterations. The proposed optimization approach named developed PSO (DPSO) is tested on the IEEE 14-bus system and compared with some existing methods. Finally, the analysis and evaluations present the effectiveness of the best current transformer (CT) settings with the minimum response time.