What question did this study set out to answer?

This research aims to improve protection coordination in microgrids using dual-setting directional overcurrent relays.

May 14, 2026Open Access

Adaptive Protection Coordination for Microgrids Using Dual‐Setting Directional Overcurrent Relays: A Real‐Time HIL Validation Approach

OMOussama MerabetUniversity of Boumerdes AKAissa KheldounUniversity of Boumerdes AAAidil Azwin Zainul AbidinUniversiti Tenaga Nasional

Key Points

This research aims to improve protection coordination in microgrids using dual-setting directional overcurrent relays.
Developed a novel optimisation approach incorporating relay operating times and coordination time intervals.
Employed the White Shark Optimiser algorithm for relay coordination across IEEE 6-bus and IEEE 14-bus test systems.
Validated the strategy through hardware-in-the-loop simulations and conducted short-circuit analysis.
Reduced total primary relay operating time significantly from 12.38 s to 6.43 s in grid-connected mode (IEEE 14-bus).
Achieved improved fault isolation capabilities compared to other metaheuristic methods.
Total primary relay operating time decreased from 14.132 s to 9.738 s in islanded mode (IEEE 14-bus) and from 6.469 s to 4.820 s (IEEE 6-bus).

Abstract

ABSTRACT Reliable relay coordination is critical for ensuring fast and selective fault clearance in modern power systems, particularly under the complex dynamics of microgrids operating in both grid‐connected and islanded modes. This research presents a robust protection coordination strategy using dual‐setting directional overcurrent relays (DS‐DOCRs) and a novel optimisation approach to address challenges in adaptive protection. A modified objective function, incorporating primary and backup relay operating times along with coordination time intervals (CTIs), was designed to enhance optimisation performance. The White Shark Optimiser (WSO) algorithm was employed to solve the coordination problem across IEEE 6‐bus and IEEE 14‐bus test systems. Short‐circuit analysis was conducted using DIgSILENT, while optimisation and implementation were carried out in MATLAB. Validation was achieved through hardware‐in‐the‐loop (HIL) simulation using the OPAL‐RT platform. The proposed method significantly reduced the total primary relay operating time from 12.38 s to 6.43 s (grid‐connected) and from 14.132 s to 9.738 s (islanded) in the IEEE 14‐bus system, and from 6.469 s to 4.820 s in the IEEE 6‐bus system. Compared to other metaheuristic methods, this approach demonstrated superior coordination performance and fault isolation capabilities. The results confirm the practicality and efficiency of the proposed adaptive DS‐DOCR scheme for improving microgrid protection reliability.

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