Research on the Influence of Distributed Photovoltaics on Distribution Network Voltage in Three-phase Unbalanced State

Abstract

The influence of traditional distributed photovoltaic grid-connected on the voltage is based on the three-phase balance state of the system, but with the development of society, more and more unbalanced loads are connected to the power grid, which makes the system in three-phase unbalanced state for a long time. Based on this, this paper considers the long-term unbalance of the system caused by the asymmetric load, and the system voltage changes in this state. Then, the change of negative sequence voltage is analyzed by the symmetrical component method, and the system is analyzed by the unbalanced power flow method in the ETAP software. The influence of distributed photovoltaic grid connection on bus node voltage under single-phase load access is studied by this paper. The results show that when the distributed photovoltaic is connected to the unbalanced system, the voltage value of each bus node of the system can be effectively improved, but the degree of influence on the system imbalance needs to be draw corresponding conclusions according to the difference of photovoltaic disconnection and load capacity.