Voltage Accelerated Directional Overcurrent Relays for Microgrid Protection

This paper proposes a voltage-accelerated directional overcurrent relay (VADOCR) based protection scheme for microgrids. The reduction in the fault current because of the domination of inverted-based renewable (IBR) power generation in microgrids has been taken care of by accelerating the operating time of relays through the fault voltage. This is achieved using a novel time-current-voltage characteristic of standard inverse definite minimum time relay. To compute the setting of the developed VADOCRs, the protection coordination problem has been formulated as an optimization problem and solved using a novel hybrid differential particle swarm optimization (DPSO) algorithm. To validate the proposed VADORCs and DPSO, the protection scheme for a standard 4-bus microgrid test system has been developed. The suitability and effectiveness of the obtained settings have been analysed. The proposed VADOCRs’ overall performance is impressive and effective in protecting microgrids in the grid-connected and islanded modes of operation.