Fault Analysis of an Inverter Interfaced Multi-Location DG Based Microgrid Under Grid Integration

This research paper presents the current and voltage level of an inverter interfaced multi-location distributed generation (DG) based power system under fault and pre-fault scenarios. The DG system simple comprises photo-voltaic cells in integration with voltage source converter (VSC). The integration of the PV based DG system with existing grid is done through current control mode of the PV set. The fault current level of a conventional grid is normally 8 to 10 times of the rated current. In inverter interfaced electrical grid, the fault current restricted to 2 to 3 times of the rated current which may lead to mal operation of the installed relay. This research assignment focuses over voltage and current level at different location of an inverter interfaced grid under a symmetric L-L-L fault scenario. The suggested current controller has anticipated a PI control scheme for making necessary control action in DG set. Since, the grid rating is high as compared to each individual DG, the major contribution for the fault current is shared by the utility grid. Finally, it is also observed that the fault current level is restricted below 3 times of the rated current due to penetration of VSC based inverter.