Interval optimization based coordinated control for distribution networks with energy storage integrated soft open points

Due to the increasing penetration of distributed generations (DGs) in distribution networks, the randomness and uncertainties of DG outputs can result in bus voltage fluctuations, affecting the power quality and power supply reliabilities of distribution networks. Therefore, this paper proposes an interval optimization (IO) based two-stage optimization method to regulate voltage fluctuations, and to improve the economy of the distribution network that contains energy storage integrated soft open points (E-SOPs) and high penetrations of DGs. The first stage establishes an IO based day-ahead optimization model to optimize the on-load tap changer and the state of charge ranges of the battery energy storage system (BESS) in each E-SOP. The second stage develops an intra-day optimization model based on the rolling optimization algorithm to optimize the active and reactive power at both sides of each E-SOP and the charging and discharging power of the BESS in each E-SOP. Furthermore, numerous simulations and comparisons are carried out on a modified IEEE 33-bus distribution network including high penetrations of DGs, and the results show that the proposed method can not only significantly reduce comprehensive operating costs of distribution networks, but also can effectively control the nodal voltage within the desired range.