Performance Evaluation of Existing Overcurrent Protection in Microgrids

In recent times, the rapid development of power systems has caused the emergence of microgrids (MGs). These new grids offer numerous benefits such as improved energy efficiency, reliability, and supply sustainability. However, the presence of distributed energy resources (DERs) introduces complexities to ensure the protection of MGs, surpassing those encountered in traditional grids. Driven by the integration of DERs in the system, changes in fault currents have occurred, contingent upon the location, capacity, and type of DERs as well as the operating mode of MGs, grid-connected or islanded mode. These changes yield adverse consequences on existing protection relays such as sympathetic tripping, bidirectional current flow, protection blindness, loss of selectivity and sensitivity, and mis-coordination. Efficient handling of these challenges is crucial to establish effective protective schemes and making the most of the MGs. This paper evaluates the effectiveness of the existing overcurrent protection approaches, aiming to investigate their effectiveness and capability to address the new challenges due to DERs integration.