A Novel Fault Detection Index in Smart Distribution System consisting Multi-Microgrids

Abstract

To ensure the better power supply and to meet the increasing power demand, the power distribution system is now equipped with multi-microgrids (MMGs). Thus, the integration of MMGs serve uninterruptable power supply to the customers increasing system reliability. The deeper infiltration of the MMGs changes the fault current characteristics when integrated in the smart distribution system network. The operation of MMGs also impact the direction and level of fault currents. The increase in the fault current contribution level may lead to false conventional relay tripping. Thus, the conventional differential overcurrent based protection methods fail to operate for the smart distribution system consisting MMGs, as these methods were usually suggested for radial networks. Moreover, the detection of low impedance as well as high impedance faults is very important in the area of differential protection in smart distribution network consisting MMGs. Thus, a novel fault detection index utilizing positive sequence angle ratio of pre fault and post fault currents, is proposed in this paper. The novel fault detection index helps in detecting and classifying the low and high impedance faults accurately ensuring better reliability. The method proposed in the paper is validated on the modified IEEE-13 bus system using Real Time Digital Simulator (RTDS).