Optimal Relay Coordination in Kampong Cham Radial System Based on Adaptive Protection Scheme Using Modified Grasshopper Optimization Algorithm

Overcurrent relays are generally used in power system protection, and proper coordination is required to ensure reliable protection. However, in radial distribution systems with multiple Distributed Generators (DGs), relay coordination becomes more challenging since fault current magnitude and direction change under different operating conditions. Although the conventional Grasshopper Optimization Algorithm (GOA) has been applied to relay coordination problems, its convergence speed may be limited when solving highly constrained optimization problems. Therefore, this paper proposes an adaptive protection scheme based on a Modified Grasshopper Optimization Algorithm (MGOA) for the optimal coordination of Directional Overcurrent Relays (DOCRs) in the Kampong Cham radial system with DG integration. The proposed MGOA improves convergence performance by modifying the control coefficient and incorporating a fitness-weighting mechanism and Simulated Annealing (SA). The study applies four different scenarios of the system, which involve DG units installed at the end of distribution lines. In comparison with conventional GOA, the proposed MGOA reduces the required iterations by 84.16%, 83.33%, 94.93%, and 95.41% in scenarios 1 to 4, respectively.