Stochastic assessment of the impact of distributed synchronous generators on voltage sags due to system-wide faults

In this paper, the authors use a stochastic approach to investigate the impact of distributed synchronous generation (DSG) on the severity of voltage sags due to system-wide occurring faults. Based on the method of fault positions, faults of various types are applied at pre-determined locations along all lines in the system and remaining voltages on the faulted phase at a monitoring point are recorded. This is done for a base case and a case with DSG. The results show with DSG, there is a general improvement in magnitudes of remaining voltage. Comparison of the populations of voltages for the two cases, using The Wilcoxon Signed Rank Sum Test, showed that these improvement are statistically significant. Further analysis showed that DSG either reduces severity of or eliminates some voltage sags. In addition, the number of expected trips due voltage sags is reduced with DSG, for any voltage sensitivity level assumed. The study concluded that incorporation of distributed synchronous generation is beneficial to the improvement of voltage sags and this should be a further incentive for their integration, especially into weak networks.