A methodology for determining fault current impact coefficients of distributed energy resources in an adaptive protection scheme

The benefits of integrating Distributed Energy Resources (DERs) within power system networks outspread into social, environmental/ecological, and economical aspects. Large-scale deployment of DERs in electricity grids bring many technical challenges, which can be better managed in small and more manageable networks, such a microgrids. One such key challenge is the protection of microgrids where bidirectional power flows, fault current contributions from DERs, and dynamic changes in the microgrid necessitate advanced protection philosophies to be developed. This paper proposes a communications-based adaptive protection scheme for microgrids with DERs. A key contribution is the development of an approach for the quantitative determination of the variance in the fault current impact factors of rotating machine generators in such an adaptive scheme with increasing distance from that generator. A microgrid test system has been proposed and PSSE simulation results are presented to formulate the approach.