Effects of correlated photovoltaic power and load uncertainties on grid-connected microgrid day-ahead scheduling

Due to the increasing integration of photovoltaic-based distributed generators (PV-DGs), uncertainties resulted from both PV-DG power and loads have posed a serious challenge in microgrid day-ahead scheduling and operation. In this study, the effect of uncertainties in both PV-DG power and loads on the microgrid day-ahead scheduling is assessed. Specifically, the correlation between the PV-DG power and load uncertainties is taken into account as this is closer to the reality. The probabilistic optimal power flow (P-OPF) model is formulated to analyse the impact of the correlated PV-DG power and load uncertainties. A modified Harr's two-point estimation method (MH-2PEM) is introduced to provide computation-efficient estimation of the P-OPF solution. Results obtained by using the MH-2PEM and Monte Carlo simulation are compared in an equivalent 44kV distribution feeder system and the accuracy and efficiency of the MH-2PEM are verified. The variation ranges of the microgrid day-ahead scheduling solution resulted from uncertainties in PV power and load are obtained with various confidence levels.