Multi-terminal phase-changing soft open point SDP modeling for imbalance mitigation in active distribution networks.

Active distribution networks (ADNs) are capable of mitigating phase imbalance caused by various operational conditions, including uneven growth of single-phase and intermittent distributed energy resources (DERs), incurring financial losses or costly infrastructure reinforcements. In this paper, the research gap for a flexible phase imbalance mitigating solution is addressed by proposing a multi-terminal phase-changing soft open point (PC-SOP). It is explored in detail on balancing the power flows and compared with other different types and ways of connection (including two-terminal and conventional). Then operational strategies based on different cases are presented for imbalance mitigation. Semidefinite programming (SDP) relaxation is utilized to convert the original non-convex nonlinear model into an SDP model which can be solved efficiently by commercial solvers. Two case studies demonstrations are conducted on IEEE 13-node and 123-node three-phase networks. It is found that multi-terminal PC-SOPs can minimize power losses by between 5.56 % and 28.98% and have better voltage control (all buses operate in the allowed voltage range [0.94, 1.10]) and less PV curtailment (reduced by at least 6.31 MW/24 h and 0.63 MW/24 h for the two test networks separately) when compared to conventional SOP technologies. • Propose a multi-terminal phase-changing soft open point to reduce phase imbalance. • Symmetrical semidefinite programming solves optimal power flow efficiently. • Power losses are minimized by between 5.56 % and 28.98%. • Achieve effective voltage regulation in the allowed voltage range [0.94, 1.10]. • PV curtailment is reduced by at least 6.31 MW/24 h and 0.63 MW/24 h in case studies. [ABSTRACT FROM AUTHOR]