Power loss analysis for low-voltage distribution networks with single-phase connected photovoltaic generation

Currently, the photovoltaic generation has been paid highly attention to and has obtained policy encouragement. With the increasing popularity of single-phase photovoltaic in low-voltage distribution networks, it may deteriorate the overall grid performance including power flows, losses and voltage pro files. On the other side, single-phase photovoltaic connected to the distribution networks will have some influence on the balance of three-phase that may bring additional losses under a three-phase unbalanced situation. In this paper, the concept of three-phase load current unbalance factor is introduced and additional losses in circuits and transformers induced by the three-phase unbalance are firstly analyzed. Secondly, the variation characteristics of the power loss and the three-phase unbalance are studied when single-phase photovoltaic is connected to different phases and different capacities. Furthermore, the paper also investigates the influence on the power loss considering different positions the photovoltaic connected along the low-voltage feeder. From the perspective of decreasing the three-phase unbalance factor, some advice for the photovoltaic connected to the distribution networks is proposed at last. The simulation results show that the proposed advice can effectively reduce the losses caused by the three-phase unbalance. It also provides effective guidance and recommendations for the electricity company to carry out loss reduction work and to deal with large-scale single-phase photovoltaic connection in the future.