Analyzing the Performance of Hybrid PSO for Optimal Directional Overcurrent Relay Coordination with Different IEC Characteristics in the IEEE ۶-Bus System

The coordination of Directional Overcurrent Relays (DOCRS) is a fundamental task in power system protection, ensuring reliable fault clearance and system stability. However, the nonlinear nature of relay characteristics and the large number of coordination constraints make this a complex optimization problem. This paper presents a comparative study between traditional Particle Swarm Optimization (PSO) and Hybrid PSO (HPSO), which integrates PSO with Simulated Annealing (SA), for the optimal coordination of DOCRS in the IEEE ۶-bus system. Three IEC inverse-time relay characteristics-Standard Inverse (SI), Very Inverse (VI), and Extremely Inverse (EI)-are investigated to evaluate their impact on relay coordination with mention methods. The objective function is formulated to minimize the total operating time of primary relays while satisfying selectivity constraints. Simulation results demonstrate that HPSO consistently achieves superior optimization performance, yielding lower objective function values and faster convergence compared to conventional PSO in coordination problems with different IEC operational characteristics. The findings confirm the effectiveness of HPSO in enhancing the robustness and efficiency of relay coordination under different IEC characteristics.

کلیدواژه ها:

Directional Overcurrent Relay (DOCR) ، Relay Coordination ، Particle Swarm Optimization (PSO) ، Hybrid PSO (HPSO) ، Simulated Annealing (SA) ، IEC Inverse-Time Characteristics ، Power System Protection ، IEEE ۶-Bus System