Real-Time Implementation of Dynamic State Estimation for Microgrid Load Bus Protection
Sarbajit Basu, Arthur K. Barnes, Adam Mate, Olga Lavrova
TL;DR
The paper tackles protection in inverter-interfaced microgrids where low fault current defeats traditional schemes. It proposes a real-time dynamic state estimation (DSE) approach with parallel estimation of multiple operational configurations, implemented on a general-purpose PC, to enable setting-less protection during faults. An orchestrator selects the configuration with the highest chi-squared confidence $p = F_{m-n}(J_i)$ and issues breaker actions, addressing data-flow and real-time decision-making challenges. Case studies in a lumped-load radial microgrid with a grid-forming inverter demonstrate rapid, robust identification of fault states and protective actions, though transitions and noise require further robustness enhancements. Overall, the work advances practical deployment of DSE-based protection by detailing a scalable, real-time architecture and its performance implications for microgrid protection.
Abstract
Inverter-interfaced microgrids, owing to the lack of fault current, cannot be protected using traditional over-current protections, while admittance or differential relaying protection schemes are not practical to be implemented. Dynamic state estimation can track and predict power system transients and has been extensively investigated for setting-less protection. A novel real-time application of dynamic state estimation for protection is proposed in this paper, wherein parameter estimation and parallel processing is used to identify the state of the system. The implementation scheme has low process complexity and employs a data acquisition device and estimator that run on a general-purpose computer. This proposed implementation extends the state-of-the-art, under short-circuit conditions, to a real-time implementation with a lumped-load radial microgrid and a grid-forming inverter with current-limiting behavior.