Probabilistic Analysis of PV Generation Impacts on Voltage Sags in LV Distribution Networks Considering Failure Rates Dependent on Feeder Loading

The impact of photovoltaic distributed generation (PVDG) in the voltage sag indices of low-voltage distribution systems is assessed in this paper. A sensitivity study of these indices in relation to the penetration level of PVDG is performed considering the effect of the feeder sections loading on their failure rates. It is showed that, when this dependence is neglected, the indices are predicted with errors, especially for scenarios with large integration of PVDG. This study was performed using clustering techniques to model the uncertainty of solar irradiation, and the state enumeration method (SEM) is used to evaluate voltage sags indices. The results obtained by the clustering method and SEM were compared with those obtained with Monte Carlo Simulation based on the beta probability density function (pdf) model for solar irradiation. This comparison showed that the clustering model can obtain indices with precision comparable to those obtained with the beta pdf model, but with a significant reduction in CPU time.