Research on Methods of Suppressing Three-Phase Unbalanced Overvoltage in Distribution Network by Substation Photovoltaic System

摘要

The unbalanced three-phase parameter of the distribution network will produce three-phase unbalanced voltage. Generally, the three-phase unbalance is suppressed by switching capacitors or reactors, but this method has limited compensation accuracy and speed. At present, many substations are undergoing the transformation of intelligent stations, one of which is to add photovoltaic systems as a supplement to energy use in the station. This paper proposes to use photovoltaic and energy storage equipment to access the neutral point of the transformer in the substation, and output the reverse voltage at the neutral point through the PWM active inverter device to realize the balanced control of the three-phase voltage of the distribution network, thereby suppressing Balance overvoltage. The simulation analysis results show that the proposed method can effectively suppress the three-phase unbalanced overvoltage, and is an effective supplementary method to improve the power quality of the distribution network.