Decentralized bilevel model for optimal planning of hybrid open points and integrated PV and energy storage systems considering diversified network coupling modes

The hosting capacity can be effectively increased by configuring energy storages (ESs) in photovoltaic (PV) plants to form integrated PV and ES systems (IPVESSs). The diversified operation modes of hybrid open points (HOPs), which are devices consisting of a soft open point (SOP) and tie switch in parallel, can further increase the PV capacity. Therefore, this study proposes a coordinated planning method for HOPs and IPVESSs. A flexible distribution network (FDN) featuring the interconnection of tie lines and HOPs is designed, and four control modes of HOPs are also analyzed. The power model of HOPs is established in consideration of the power flow direction of the tie lines and SOP. Then, a bilevel optimization model of HOP and IPVESS planning is constructed. The capacity and location of HOPs and IPVESSs are determined by the distribution company and distributed energy resource aggregators, respectively. To solve the bilevel multiagent mixed-integer nonlinear programming problem, we further propose an analytical target cascading method embedded with strengthening convex relaxation. The case studies demonstrate that HOPs reduce the total cost of FDN by more than 18 %, and the proposed algorithm requires approximate five and nine iterations respectively to make the upper-level and the bilevel model converge.