Adaptive Protection System for Microgrids

Abstract

The evolution of electric power systems has seen a significant trend towards decentralizing and distributing power generation, primarily through the embracement of Distributed Energy Resources (DERs) like solar photovoltaics, batteries, demand response generators and wind turbines. This trend has seen the emergence of microgrids which are small scale grids that can operate independently or in combination with the main grid. However, the dynamic nature of microgrids, characterized by frequent topology modifications due to switching operations, varying DER outputs, and mode switching between grid-connected and islanded operations, introduces difficult challenges to traditional protection schemes. The static nature of traditional protection settings makes them difficult to adjust to these changes, and as a result, miscoordination and unexpected outages follow. This research explores the development of an adaptive overcurrent protection scheme for microgrids of diverse topological configurations. The study emphasizes the real-time dynamic adjustment of relay set points based on topology modifications to ensure ideal protection coordination. Based on the utilization of advanced algorithms and communications protocols, the proposed system dynamically readjusts protection settings by considering factors such as changes in fault currents and DER availability. To verify the system, we used OpenDSS for system simulation and Python for automating the verification of different scenarios. The principal objective of this thesis is to enhance the reliability and robustness of microgrid protection systems in response to topological shifts. By using an adaptive overcurrent threshold setting method, the research aims to ensure reliable and quick fault detection and isolation during different microgrid configurations. Furthermore, our objective focuses on minimizing the exposure of protection miscoordination due to dynamic operating conditions when different types of DERs are integrated. The outcome of this research is projected to serve a key part in designing vigorous, adaptive protection mechanisms, resulting in more flexible and protected microgrid operations.