Microgrid Short Circuit Studies

The microgrid are small autonomous power networks equipped with power generating sources. The photovoltaic based generating systems with battery based energy storage are key elements for reliable operation of microgrid. In this research article, an equivalent short circuit model is proposed for short circuit studies to evaluate the contribution from dc side and utility side of microgrid. The detailed simulation studies are carried out to find the fault feeding capabilities during different operating modes of the microgrid. It is observed that fault current contribution is extremely low in PV and battery modes as compare to the utility connected mode of microgrid operation. The low/weak fault feeding capability of PV and battery based sources created protection complexities for detection of faults with conventional over current based relaying schemes. The proposed simulation is carried out in the RSCAD simulation package of real time digital simulator. The simulation results are validated against the manual calculation carried out through the equivalent circuit model reduction technique.