An analytical literature review of the available techniques for the protection of micro-grids

During the last decade, besides the rapid increase in the penetration level of Distributed Generation (DG) units of micro-grids, the connection of micro-grids as a developed technology to the existing distribution networks has also attracted much attention. One of the major challenges associated with the protection of micro-grids is to devise a proper protection strategy that is effective in the grid-connected as well as the islanded mode of operation. In order to deal with the challenge, many researchers have recently proposed various techniques. The purpose of the current study is to provide a comprehensive review of the available protection techniques that are applied to address micro-grid protection issues in both grid-connected and islanded mode. The most up to date relevant options are described and categorized into specific clusters. A comparative analysis is carried out in which the advantages and disadvantages to each technique are assessed. Lastly, after the appraisement of the existing protection techniques, some conclusions and suggestions are put forward for the protection of micro-grids in the future.