Detection of Voltage Sag Source in a Hybrid Microgrid Using Directional Relays

Abstract

The proliferation of hybrid microgrids incorporating renewable energy sources has introduced significant challenges in power quality management, particularly in the detection and localization of voltage sag sources. This research investigates the application of directional relays for accurate identification of voltage sag origins in hybrid microgrid systems. The study employs a comprehensive methodology combining simulation analysis using MATLAB/Simulink with real-time hardware implementation to evaluate the effectiveness of directional relay-based detection algorithms. Primary data collection involved experimental validation on a laboratory-scale hybrid microgrid comprising photovoltaic systems, wind turbines, and energy storage units. Secondary data analysis encompassed existing literature on voltage sag detection methodologies and directional relay applications in distributed generation environments. Results demonstrate that directional relays equipped with advanced signal processing algorithms achieve 94.7% accuracy in voltage sag source localization, with detection times averaging 0.8 cycles. The proposed methodology significantly outperforms conventional voltage-based detection techniques, particularly in scenarios involving bidirectional power flows characteristic of hybrid microgrids. Implementation challenges include relay coordination complexity and communication infrastructure requirements. The research contributes to enhanced power quality monitoring and fault diagnosis capabilities in modern distributed energy systems, providing a foundation for improved grid reliability and reduced economic impacts of voltage disturbances.