Spatio-Temporal Decomposition and Coordination for Distributed Load Restoration in AC/DC Hybrid System

A new spatio-temporal decomposition and coordination scheme is proposed for load restoration in an AC/DC hybrid transmission system. First, the framework of spatio-temporal decomposition is built for load restoration, the decoupled variables and spatial and temporal coordinators are defined, as well as two interactive blocks. Furthermore, the spatio-temporal decomposed models of subsystems and HVDC links are constructed considering security constraints and HVDC operation characteristics. Finally, a new hierarchical overlapping coordination based analytical target cascading (HOC_ATC) algorithm is developed to coordinate the decomposed models by iterative calculations between subsystems and coordinators, as well as the two interactive blocks. The proposed distributed scheme maintains independent operations of subsystems, and handles the multi-step restoration process by iteratively calculating single-step models. The developed HOC_ATC algorithm provides tractable and efficient computation for the HVDC model incorporated load restoration optimization. The effectiveness of the proposed method is validated using two IEEE test systems, showing improved computational efficiency and better convergence ability.