Advanced Rapid Directional Over-Current Protection for DC Microgrids Using K-Means Clustering

Over-current (OC) protection is one of the often-used protections in DC microgrids. Its rapid operation, critical for protecting the system, is a key reason for its widespread use, as it plays a pivotal role in swiftly isolating fault conditions and preventing potential damage to the microgrid components. However, activating OC in DC microgrids comes with several challenges. These challenges range from the DC microgrid's grounding to the extremely rapid rise time of the fault current. This research presents an adaptive directional OC method for DC microgrids utilizing the IEC 61850 communication protocol. The proposed method employs K-means clustering to define setting groups for OC relays. The presented approach enhances the reliability and performance of OC protection in DC microgrids, by combining communication technology and advanced protection algorithms. Notably, it achieves instantaneous protection speed while maintaining protection coordination. The method utilizes a communication network, offering adaptability to different fault scenarios, even with a partially covered communication network. It significantly reduces maloperations during overloads and applies to various grid topologies. The scheme's effectiveness is evaluated in terms of speed and selectivity through extensive simulation and experimental testing using MATLAB, RT-Lab, Python, and OPAL-RT real-time simulator. This article showcases the practical application and advantages of communication-assisted OC protection in DC microgrids.