Reliability Assessment of Ring and Radial Microgrid Configurations

This paper analyzes the qualitative and quantitative reliability of a DC Microgrid (MG) using fault tree analysis (FTA). Reliability analysis considers DC MG in both ring and radial configurations. The reliability objective is to support a critical load. For ring configuration, repeated events can happen, which results in an incorrect reliability calculation of the reliability objective. Therefore, Relyence software is used to build the DC ring MG fault tree (FT), to eliminate the repeated events. Then, the reliability of the DC ring MG is compared with the reliability of the single bus DC radial MG. Results show that failure probabilities for the ring and radial configurations are 0.049539 and 0.051857, respectively. Hence, the DC ring MG is more reliable than the DC radial MG. Finally, the reliability of the DC ring MG in the islanded mode is investigated.