Fault Protection Analysis of a DC Microgrid Using VSC-Based Modular Multilevel Converter (MMC)

Abstract

DC microgrid development is increasing mainly due to its simplicity of operation and greater focus on renewable energy sources like solar, wind, etc. It comprises less losses than AC microgrid and can easily connect and disconnect distributed generation (DG). Conventional techniques of DC microgrid protection is challenging. Using MATLAB Simulink, a DC microgrid with a PV system, battery, and AC main grid along with converters including boost, buck, and voltage source/modular multi-level converters is simulated. This study compares the performance of modular multilevel converters and voltage source converters, as well as the way they protect DC microgrid in the case of an AC main grid fault condition. Additionally, for improved fault clearing response in overcurrent situations, the differential relay is used on the AC main grid, nearer to the transformer.