Optimal Dispatch of Power Electronic Transformer Embedded AC/DC Hybrid Distribution System

With the development of power electronics and the higher penetration of renewable energy sources, power electronic transformer (PET) becomes a prospective device for future AC/DC hybrid distribution system. Based on second order cone programming, this paper proposes a multi-period dynamic optimal dispatch model for the multi-port PET embedded AC/DC hybrid distribution system, which focuses on the convex relaxation of the power flow constraints. The steady-state mathematical model considering the exact power loss of PET is established, multiple control modes and corresponding control variables of PET are given. The proposed two-stage joint optimization of PET AC/DC ports and active-reactive power of schedulable resources aims at improving the flexibility of power flow control to minimize the operation cost and power losses in the hybrid distribution system. The security operation of PET and the system is also considered. Case study results verify the necessity and superiority of the proposed optimal dispatch model and the renewable energy source curtailment is decreased.