Review and analysis of existing protection strategies for micro-grids

Micro-grids are becoming increasingly attractive to consumers and in the near future, a great number of them will be installed in consumer's sites. One of the major difficulties associated with the implementation of micro-grids is to explore a suitable protection strategy which is able to protect them in both modes of operation, that is, the grid connected mode and the autonomous mode. To remedy the difficulty, various strategies have been recently proposed in the literatures. The objective of this paper is to provide a comprehensive review of the existing protection strategies deployed for addressing micro-grid protection issues in both grid-connected and islanded mode of operation. In addition to description of available protection strategies to date and classifying them into certain groups, a comparative analysis is accomplished in which the benefits and drawbacks of each strategy are evaluated. Finally, after the evaluation of various protection strategies, some conclusions and recommendations are put forward for the micro-grid protection in the future