Effect of type and interconnection of DG units in the fault current level of distribution networks

Fundamental requirements for the connection of distributed generation resources to the network are not only power quality constraints, but also voltage regulation and the total fault level, which should remain below the network desired value. This constraint is often the main limiting factor for the interconnection of these resources units to the grids. In the presented paper, the impact of installation of distributed resources in the distribution systems from the perspective of increase in the fault contribution will be discussed and comparative study will be performed to analyze the effect of type and interconnection of distributed generation unit on the fault current contribution of the distribution systems. Simulation results indicate that the increase in fault currents is often greater in the synchronous machine implementation versus a comparable inverter based design.