An Interval Optimization Based Two-stage Voltage Control Method for Distribution Networks

This paper proposes an interval optimization (IO) based two-stage voltage control method, fully considering the uncertainty and randomness of photovoltaic (PV) and load power. In the centralized stage, the coordinated optimization model of the on-load tap changer (OLTC) and multiple PVs based on the IO is established, to periodically (30 min) optimize the tap position of the OLTC and coefficients of the voltage-var droop control curve for each PV. In the local control stage, according to the measured voltage and the updated voltage-var droop control curves at PVs' connection nodes, the reactive power of each PV is adjusted in real time (1 min) to suppress voltage fluctuations. Furthermore, numerous simulations and comparisons are carried out on a modified IEEE 33-bus distribution network with high penetrations of PVs, and results show that the proposed method can not only effectively deal with the problem of node voltage violations, but also significantly reduce the power loss of distribution networks and the adjustments of the OLTC.