Three Phase Unbalance Control Method Based on Coordinated Control of Adjustable Resources in Distribution Network

Abstract

Aiming at the problem of three-phase voltage unbalance caused by the probabilistic output of single-phase distributed photovoltaic (DPV) in distribution network, the method of coordinated operation of DPV reactive power regulation and capacitor bank to control three-phase voltage unbalance is studied. The relationship between the reactive power of single-phase DPV output and the three-phase unbalance degree of the grid-connected common connection point is analyzed. The influence of the reactive power of the capacitor bank on the three-phase unbalance degree of each node is deduced. The output value of DPV is calculated based on the prediction results of solar irradiance. Aiming at the three-phase unbalance of the common connection point not exceeding 2%, the reactive power regulation is given according to the derivation relationship between the reactive power of each equipment and the three-phase unbalance, so as to ensure that the three-phase unbalance in the station area is limited within the required range. Finally, the correctness and effectiveness of the method are verified by the data calculation of a station in Jiangsu Province.