Microgrid Protection

Abstract

Designing an overall protection system for the installation of a microgrid is a major technological problem. For both grid-connected and islanded operation, the general specification like sensitivity, reliability, and selectivity must be met by the protection system. Different researchers have proposed different types of protection system for low and medium voltage microgrids. The traditional protective devices that rely on the overcurrent method cannot provide overall protection for the microgrid, so a new protection system is a must. According to the operational mode of microgrid the new protection system must be adaptable as well as sensitive so that it can identify and clear the smallest fault currents. This thesis's main objective is to review AC microgrids' protection issues, and present other available protection systems for AC microgrids developed and recommended. In this thesis, a substantial literature review on the protection and solution of AC microgrid is presented. The conventional microgrid protection challenges are presented, and also, the faults in grid-connected mode and islanded mode are discussed. The protection solution for grid-connected mode, islanded mode, and for both of them is presented. From the review, it is observed that an adaptive protection policy is the most suitable for a microgrid protection solution. The relay settings can be changed, and the necessary protection can be provided in an adaptive protection system with the topological and operational change. An adaptive protection system can solve the protection problem of the grid-connected and islanded mode operation. A communication system is needed for most of the adaptive protection systems in grid-connected and islanded operations, so communication enhancement is significant for the future microgrid.