The faults variability in distribution systems with distributed generation and robustness of smart grids

Although Distributed Generation (DG) is a sustainable alternative to meet the growing demand for electricity, the intermittency of its primary sources and operational variability introduces additional uncertainties to the Power Distribution Systems (PDS). Because of great potential for penetration of DG in the PDS, it is important to investigate the DG impact to the grid´s safety and reliability. To contribute to such investigations, this article reports on a study of the variability in fault currents and voltages measured in the power distribution substation. Computer simulations of a system with DG were conducted based on the IEEE 13 Node Test Feeder. The analysis was based on the calculation of the apparent impedance of the faulty phase. For that there was variability greater than 30% in the magnitude and 15% in the angle. These results highlight the need for greater robustness in fault location or operation of the system under the concept of smart grid.