Alex Sandria Jaya Wardhana, Dwinugroho Putro Utomo, Sarwo Pranoto
This paper proposes a unified swarm intelligence framework for optimal overcurrent relay (OCR) coordination under the IEC Standard Inverse (SI-IEC) characteristic, selected as the primary optimization target based on a ten-family IDMT baseline characterisation. The problem is formulated as a constrained nonlinear optimization model with coordination time interval (CTI ≥ 0.3 s) enforced via a hybrid constraint-handling strategy combining boundary control, adaptive penalties, and feasibility repair. Four algorithms (PSO, ABC, ACO, GWO) and their adaptive variants are evaluated on an IEEE 8-bus system under identical conditions. Results show that adaptive mechanisms significantly improve performance, achieving up to 38.64% reduction in total operating time (4.558 s to 2.797 s). The best method (GWO-M) attains the highest convergence rate (96.7%), fastest convergence (44.5% iterations), and lowest variability ( σ = 0.055 s), while satisfying all coordination constraints. The benchmarking results further confirm that GWO-M demonstrates competitive performance with recent post-2024 methods under comparable evaluation conditions. This article is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. https://creativecommons.org/licenses/by-sa/4.0/
Electrical Engineering Education Department, Faculty of Engineering, Universitas Negeri Yogyakarta, Yogyakarta, Indonesia
