Adaptive Protection for Preserving Microgrid Security

The low inertia renders renewable-based microgrids (μGs) more susceptible to incipient faults and makes it more difficult for distributed systems to maintain a reasonable margin for dynamic security. This paper studies the μG security using a three-stage approach to the power system protection. The first stage considers offline analyses of synchronous generator-based distributed energy resources (SGBDERs) and inverter-based distributed energy resources (IBDERs) for establishing dynamic security models in μGs. The required data and settings are also determined at this stage. The second stage uses the first stage models for the online calculation of equilibrium points, regions of attraction, and protection zones for SGBDERs and IBDERs operations. This stage adapts to different conditions for μG operations. The third stage is responsible for the real-time protection of μGs. This stage uses the real-time data for the fast detection of dynamic security status and protection of μGs. Simulation results presented in the paper demonstrate the adaptive features of the proposed scheme.