Source-load-storage consistency collaborative optimization control of flexible DC distribution network considering multi-energy complementarity

摘要

Due to the increasing coupling degree of the power network, natural gas network, and thermal network, this paper discusses a flexible DC power distribution network based on the consistency algorithm theory regarding the advantages and disadvantages of centralized control and distributed control. A layered network control architecture is presented. Considering the multi-time-scale control characteristics of the system, the control architecture is divided into three layers: energy management layer, bus control layer, and converter control layer. In the energy management layer, the dispatch optimization center optimizes the system operating cost through the multi-objective energy optimization management of the integrated energy system consisting of the DC distribution network, natural gas network, and heating network. In the bus control layer, the DC bus voltage is taken into account. The control characteristics are divided into three categories corresponding to three working modes according to the range of the DC bus voltage, which is used to realize the conversion mode control of every distributed device in the distribution network. In the converter control layer, based on the original droop control, the voltage and frequency deviations of every distributed device are compensated twice, and every distributed device controller communicates only with the adjacent controller to achieve the voltage and frequency consistency control with the "virtual leader" node. Finally, using the typical eight-terminal VSC flexible DC distribution network control architecture, the proposed control strategy is verified by the PSCAD/EMTDC simulation software.