Probabilistic sizing of low voltage microgrid-forming resources: Technical approach and regulatory assessment in the brazilian context

Power distribution reliability concerns several low voltage consumers in Brazil. Large investments are needed in infrastructure to guarantee continuous supply, especially during adverse weather conditions. An alternative to conventional structural investments considers distributed energy resources to form low voltage microgrids that can operate islanded during faults in the primary distribution. In this paper, the potential for microgrid integration is evaluated considering both technical and regulatory aspects in Brazil. First, the main characteristics and configurations of secondary distribution grids adopted by distribution utilities are assessed. Next, a methodology is proposed for assessing the potential for integrating low voltage microgrids. Finally, the current regulatory framework regarding the possible applications of low voltage microgrids in Brazil is assessed, followed by policy recommendations to leverage such alternative. Two case studies demonstrate the applicability of the methodology, and the results suggest that even small energy storage systems (as small as 25 kWh) can reduce considerably the number of interruptions in over 80 % of the low voltage circuits of the utility under study. Although the case studies were developed considering the Brazilian context, the proposed methodology is flexible enough to be applied in other scenarios, which is potentially useful for system planners and regulators.