Protection Coordination System for a Converter Dominated Standalone DC Microgrid

Abstract

In this work, a reliable coordination system between fast protection devices and power electronic converters in a standalone DC microgrid is presented. The system is a standalone DC microgrid which is supplied by the distributed energy resources of an emulated wave energy converter and an energy storage unit. A system model that includes solid-state circuit breakers is developed in PLECS to analyze the steady-state operation as well as faulted conditions. Fault diagnosis and detection have been carried out in different segments of the system for both overcurrent and short-circuit faults. An effective protection coordination system is developed considering current limiting operation of power electronic converter during fault to ensure rapid fault isolation and continued power delivery to the healthy segments. The protection algorithm demonstrates reliable system operation and fault isolation during an event of overcurrent or short-circuit fault. Experimental results are presented to validate successful operation of the solid-state circuit breaker in a 380V DC system.