Reliability Evaluation of Grid-Connected Microgrids with High Penetration of Renewable Distributed Energy Resources

Abstract

Creation of microgrids in distribution networks under fault conditions is a well-known solution for improving network reliability. In order to provide operation in islanded mode, microgrids require advance control functionalities and an adequate level of distributed energy resources. However, variable renewable generation introduces several constraints with respect to possible network reliability improvements to the microgrid approach. This paper addresses these constraints and evaluates the options for reliability improvement of microgrids with high presence of renewable generation. Load shedding, energy storage, distributed generation and creation of smaller microgrids within a microgrid are all evaluated. The reliability improvements of these solutions were demonstrated by using an 11 kV island microgrid connected to a wider mainland network. The evaluation results identified the further opportunities for the supply reliability improvements in microgrids based on renewable and storage technologies.