Micro-grid research is being performed due to installation of renewable energy sources and ESSs, and demonstration projects on a community micro-grid for the self-energy supply rate are being carried out in Jeollanam-do province in South Korea. A comm...
Micro-grid research is being performed due to installation of renewable energy sources and ESSs, and demonstration projects on a community micro-grid for the self-energy supply rate are being carried out in Jeollanam-do province in South Korea. A community micro-grid may be operated as a type of grid-connected micro-grid when the self-energy supply rate is 50%. An operation method for protection devices is required because the magnitude and direction of the fault current may be changed depending on the location and type of the fault. Therefore, this paper proposes an operation algorithm for protection devices that considers the location and type of the fault in order to properly perform protection coordination in grid-connected micro-grid. We modeled a grid-connected micro-grid, which was composed of an ESS, PV system, and geothermal plant, and we used PSCAD/EMTDC S/W in order to analyze the fault current characteristics in the case of a short circuit and single-line ground faults. The simulation results confirmed that the proposed algorithm is useful to operate protection devices in a grid-connected micro-grid because the coordination time intervals were properly obtained.