Abstract:
With the large-scale integration of distributed photovoltaic (DPV) in the distribution network, voltage exceeding limits and fluctuations are becoming increasingly severe. The voltage and reactive power optimization and coordination control method considering new power quality management devices needs to be further improved to adapt to the new changes in the power grid. This article considers the power quality regulation effect of the new flexible on-load tap changer (OLTC) and proposes a two-stage voltage and reactive power optimization coordinated control method. The first stage is the day before hour level scheduling stage. Based on distributed photovoltaic and load prediction data, the active output results of DPV and the switching results of flexible OLTC taps and capacitor banks are obtained through power flow calculation and iterative optimization. The second stage is the minute-level reactive power optimization stage. Based on the first stage, considering the reactive power output characteristics of flexible OLTC and DPV, adjusting the reactive power output of the equipment while correcting the capacitor bank switching combination in the first stage, further reducing the maximum voltage deviation of each node and making the distribution network voltage distribution more reasonable. An IEEE33 node distribution system simulation model is built in the paper. The proposed two-stage voltage and reactive power optimization coordination control method considering flexible OLTC can improve the DPV absorption level by 9.29% based on the conventional economic optimal goal of 88.07%, while meeting the requirement that the voltage deviation of the entire node is less than 0.1pu During the entire period, the overall economic efficiency improved by 7.8%. The results demonstrate the rationality and effectiveness of the proposed method.